The present invention relates to a system for sensing a crank angle of an internal combustion engine, and a control system for controlling a timing of the engine such as ignition timing and/or fuel injection timing.
A crank angle sensor is conventionally used in an electronic control system for an internal combustion engine, to determine an ignition timing (an angle of advance for ignition) and/or a fuel injection timing (a timing of start or end of fuel injection). The crank angle sensor produces a reference angle signal each time a reference crank angle position of each cylinder (BTDC 70.degree., for example) is reached. Furthermore, the crank angle sensor produces a unit angle signal in each angular displacement of a unit crank angle (1.degree., for example). The instantaneous crank angle position of each cylinder can be determined from the crank angle position at which the reference signal is generated, and the number of occurrences of the unit angle signals after the generation of the reference angle signal.
Because the reference angle position is thus used as a standard for measurement of the crank angle, the mounting position of the crank angle sensor must be adjusted accurately in the engine assembly process. The adjustment is normally done by monitoring the ignition position, and accordingly the adjustment is troublesome and time consuming.